Encapsuling device for expanders, compressors or the like



Dec. 5, 1961 P. AUDEMAR 3,011,694

ENCAPSULING DEVICE FOR EXPANDERS, COMPRESSORS OR THE LIKE 4 Sheets-Sheet1 Filed Sept. 2, 1959 Dec. 5, 1961 P. AUDEMAR 3,011,694

ENCAPSULING DEVICE FOR EXPANDERS, COMPRESSORS OR THE LIKE Filed Sept. 2,1959 4 Sheets-Sheet 2 P. AUDEMAR 3,011,694 ENCAPSULING DEVICE FOREXPANDERS, COMPRESSORS OR THE LIKE Filed Sept. 2, 1959 4 Sheets-Sheet 3Dec. 5, 1961 O O O FIG.3

Dec. 5, 1961 P AUDEMAR OR THE LIKE Filed Sept. 2, 1959 ENCAPSULINGDEVICE FOR EXPANDERS, COMPRESSORS 4 Sheets-Sheet 4 1 \f I n @zgezvbolUnited States Patent" 3,011,694 ENCAPSULING DEVICE FOR EXPANDERS,COMPRESSORS OR THE LIKE Pierre Audemar, Mnlhonse, France, assignor toSociete Alsacienne de Constructions Mecaniqnes, Mulhonse, Haut-Rhin,France, a company of France Filed Sept. 2, 1959, Ser. No. 837,682 Claimspriority, application France Sept. 12, 1958 1 Claim. (Cl. 230-146) Thisinvention relates to rotary machines such as rotary engines and pumps,for example, a rotary engine operated by expansion of an elastic fluidunder pressure or operable as a pump to compress said fluid. In theFrench Patent No. 980,737, a rotary machine, more particularly forexpanding or compressing gas, is disclosed which comprises two parallelplates or discs and, interposed therebetween, two volute partitions, onecarried by each plate, which bear against the surface of the oppositeplates, the spirals or volutes being such that if they are moved so thattheir relative movement corresponds to homokinetic rotations aroundsuitably eccentric axes, they always remain tangential to one another attwo points of each of their convolutions.

In the embodiment described in the aforesaid French specification thetwo discs were rotated homokinetically i.e. at the same speed at anyinstant, around two offset centres. However, the description thereinalso stated that one of the discs could remain stationary and therequired relative movement could be produced by a translational movementof the other disc over an appropriate path. 7

One of the disadvantages of this known machine is that the fluid iscompressed between the two discs and therefore tends constantly toseparate the same from one another, leading to a considerable axialreaction on the shaft or shafts of the device. This disadvantage is allthe more noticeable because this kind of machine usually has to dealwith very highly compressed fluids.

A number of earlier machines of the same kind are known whereinendeavours have been made to reduce the axial reaction by using a flatrotor which is spirally ribbed on both its surfaces and which isreceived in a stator chamber subdivided by spiral partitions conjugatedwith the rotor ribs. I

All the known machines, however comprise a central driving mechanismwhich has a number of disadvantages.

First, the very presence of a central mechanism makes it impossible tooriginate the spirals near the axis; yet, as is well known and as Willbe referred to later in the detailed description of the presentinvention, the elficiency of this kind of machine increases rapidlytowards its axis, both for compression or expansion.

Also, gas pressure is highest near the axis, and so a driving mechanismwhich extends through the casing near the axis leads to very difiicultproblems of sealing tightness. Finally, such a mechanism is at leastpartly subjected to the action of the fluid which may in some cases bydangerous to satisfactory operation.

This invention has as its subject matter an encapsuling device of thekind previously mentioned comprising a double-surface moving disc, thetransmission mechanism consisting solely of means disposed beyond theperiphery of the spirals. The moving disc will hereinafter be referredto as a rotor by an extension of the sense of that word, although themovement of the disc is actually a circular translational movement.

The device can therefore be rendered highly efiiecient by originatingthe spirals at a distance from the axis limited in practice only by thediameter of the central fluid inlet or outlet aperture. The problems ofsealing tightness in the high-pressure area are thus obviated. Finally,trans- 3,011,694 Patented Dec. 5, 1961 mission mechanisms connected tothe rotor beyond peripheral sealing means are, of course removed fromany action by the fluid. This latter advantage is particularlyinteresting in an application for which the invention is moreparticularly but not exclusively intended, i.e. the expansion ofcorrosive gases at the exit of wells, with recuperation of some of theirenergy.

In a preferred embodiment of the invention, the rotor spirals and statorspirals consist of involutes of identical circles, the rotor "spiralsbeing offset by relatively to the stator spirals, and the rotor movementis transmitted by at least one eccentric combined with guide means, theassembly forcing the rotor to move translationally along a circular pathon a diameter equal to the pitch of the spirals less twice the constantthickness of the partitions. Each of the spiral partitions of the rotoris therefore constantly tangential to the associated spiral partition ofthe stator at two points of each of its convolutions.

The aforesaid guide means can be unitary with the eccentrics if the sameare provided to a suflicient number (at least two).

In a preferred embodiment of the invention the rotor is formed on eachsidewith two central orifices supplying the stator chamber, suchorifices constantly communicating with one another by way of a gapextending from one side of the rotor to the other.

The apertures can therefore be of half the crosssection of theconventional single aperture. Also, the rotor is completely balanced inthe area of maximum pressure. To improve balance still further, therotor is formed with a number of apertures which extend through therotor preferably near the periphery of its ribs.

For instance, where gases issuing from a well at a very high pressureare to be expanded, the forces applied by the rotors to the eccentricsor vice versa are very high and the shafts of the eccentrics aresubjected to considerable radial forces. According to the invention, toobviate'this disadvantage two twin rotors are used which are out ofphase with one another by 180' so that the radial forces applied to theshafts largely compensate for one another.

Of course, this arrangement is not limitative and n rotors ofiset bycould be provided. Where at least two rotors are used, the adjacentcompartments of the two stators can be supplied through a single duct.

Without departing from the scope of the invention a number ofcompression or expansion stages can be provided each formed by a deviceas hereinbefore described, the periphery of the chamber or chambers ofeach stage communicating with the central apertures of the followingstage possibly by way of a cooler or pre-heater.

The invention also relates to a numberof particular constructional stepsconcerning, inter alia, the peripheral sealing means, the manner ofderiving a movement from the eccentric or eccentrics or the mechanismfor driving such eccentric or eccentrics.

Other objects and advantages of the invention will be hereinafterdescribed with reference to the accompanying drawings, given merely byways of example.

In the drawings:

FIG. 1 is a partial profile view, with the casing removed, of a rotarymachine according to the invention, a'partial section being taken alongthe line I"I of FIG. 2;

FIG. 2 is a sectional view taken along the line IIII of FIG. 1; it willbe noted that this section line is staggered at the top relatively tothe vertical in order to show clearly the central supply system for themac a;

, FIG. 3 is a partial view corresponding to FIG. 1, but on an enlargedscale, 'of the spiral partitions of the machine, and

FIG. 4 is a sectional view on an enlarged scale of the lower part ofFIG. 2.

The machine illustrated,rwhich is intended for expanding gases, has aframe which comprises two members 1, 2 formed with circular recesses 3,4 respectively receiving stationary discs 5, 6 each forming one of thewalls of one of the two stators of the machine. In the exampleillustrated, the stators and the rotors are in the form of circulardiscs. This circular shape is very advantageous, particularly inconnection with the transmission of the movement to the eccentrics. Thediscs 5, 6 are centered on the members 1, 2 of the framework by means ofprojections 7, 8 received in locating sockets 9, 10 in the frame. Thestators are completed by a common central stationary disc 11. A rotorconsisting of a moving disc is received in each of the chambers formedbetween the adjacent surfaces of the end discs and 6 of the'stators andtheir common central disc 11. The tworotors are designated by numerals12 and 13. In the example illustrated each face of the stators androtors 'bears a spiral partition formed by an involute of acircle.However, suitable spirals of the kind hereinbefore specified could beproduced by other constructional methods, more particularly in the formof involutes of convex geometrical figures other than a circle.

As previously stated, since there is no transmission mechanism in thecentral part of thedevice, the spirals can originate at avery muchreduced distance from the axis. FIG. 3 approximately illustrates spiralsin the form of involutes of a circle which uses this possibility to themaximum.

Referring to FIG. 1, the outline of a few central convolutions andof afew peripheral convolutions of the two, spirals are shown.

In FIG. 3, it will be immediately apparent that the two spirals 16, 17are tangential to one another at two points of each of theirconvolutions. For instance, so far as the first convolution isconcerned, the two spirals are tangential at 21 and 22. In the positionillustrated these two points of tangency bound a closed chamber 23communicating with the central aperture 14 of the stator.- Thehigh-pressure gases entering through the aperture 14 tend to increasethe volume of the chamber 23, so that there is a tendency for that partof the rotor turn lying between the two tangency points 21, 22 to beseparated from that part of the stator turn lying be tween the same twopoints; The rotor is thus moved intranslation and moves along itscircular path clockwise. After some circular translational movement fromthe position shown in FIG. 3, the inner end of the spiral 17 of therotor engages with that of the stator spiral 16 and divides the chamber.23 into two equal compartments. Immediately after a new chambersimilarto 23 is formed,

which communicates with the aperture 14. The mass of gas which was inthe preceding chamber 23 is now,

enclosed in :two completely closed chambers 24, 25 wedging in eachother, the volume of which continues to increase as thetranslational'movement of the rotor continues. After two revolutions ofthe rotor the procedure hereinbefore described is repeated and a thirdcentral chamber, as 23, isformed, surrounded by two other completelyclosed chambers, as 24, 25, while the latter, still closed have taken upthe positions 24, 25,

whereafter the same chambers take up seriatim the positions 24", 25" andfinally 24" and 25" until their outer endsopen as shown at 70. Theexpanded gases are then collected along the periphery of the device byapertures 60. 'Within the machine, therefore, there is always a centralchamber in which the gases act on the rotor to which they impart acontinuous circular translational movement, the central chamber beingsurrounded byia plurality of expansion chambers in which all the energyof the gases helps to drive the rotor. It will therefore be readilyapparent that with such a machine, which takes up little space, ,a veryconsiderable amount of energy can be recovered and a considerableexpansion of the gases can be provided. For instance, using a specificdesign very similar to the one illustrated here and taking up a totalamount of space of the order of 1 m. in diameter and 2 m. in length,machines have been built which recuperate almost 1500.H.P. whileexpanding 24 litres of gas per second from 400 to kg./cm.

The five discs of the embodiment illustrated in FIGS. 1 and 2 are heldtogether by two rows of bolts 26, 27, the first of which bears spacingrings 28 for maintaining the discs 5, 6 and 11 of the, stator far enoughapart from one another so as not to jam the rotor discs 12, 13. Theother bolts 27 have centering sleeves 58 and ensure rigid assembly ofthe whole.

Each of the discs 12, 13 is rigidly secured tothe outer races 29 ofeccentric ballbearings, the inner-races 30 of which are fitted aroundeccentrics 31 rigidly secured to shafts 32.

In the example illustrated six shafts 32 are each provided with twoeccentrics, the shafts 32 being-regularly spaced on the samecircumference around the axis of the device. This arrangement is notessential since the movement concerned is not a rotation but a circulartranslational movement. However, this arrangement is convenient fortransmission of the movement, as it enables a number of identicalpinions 34 to be placedaround a central gearwheel 33, each pinion 34engaging with the central wheel 33 and being secured to one of theshafts 32. Transmission of the movement starts from the central wheel 33which is secured to a central shaft 35. The compressed gas which it isrequired to expand is supplied through a duct 36 and three inlet pipes37, 38, 39cmnecting the duct 36 to the central apertures 4043of thestators. It will be noted that the pipe '38'has twice the cross-sectionof the pipes 37 and 39 so as to distribute the incoming gas uniformlybetween the four stator apertures. The axial holes 45, 46 of the rotorsalso help to balance the gases between the two surfaces ofthe rotors.Also, the peripheral holes 47 helpto balance the pressures at the exitof the gases. One of the stators (the right-hand stator in FIG. 2)communicates With the other by peripheral holes 48; the expanded gasesare collected by a number of pipes 49 communicating with peripheralapertures 60 disposed near the periphery of the left-hand stator; thegases flow into an annular collector 50 and are exhausted through anexhaust pipe 51. Peripheral scaling is provided by two sets ofconcentricn'ngs which are constantly applied to the surface of the rotordiscs by springs 52 separated from one another by equal angularintervals. The inner rings 53 are separated from the outer rings 54 byan annular chamber 55 which communicates with ports 56 for leakageremoval or oil injection. The transmission mechanisms, which areentirely outside the rings 54, are thus fully protected by thisarrangement, for even if there is slight leakage of the inner rings 53,the gas escapes more readily through the annular chamber 55 and ports 56thanalong the outer rings 54. The inner rings 53 improve theireifectiveness still further, and are provided with inclined lips 57resting on the rotor discs only by their thinned inner edges.

This step makes it possible to predetermine the bearing pressure of therings 53 by suitably positioning the lips 57.

While the invention has been described with particular reference to apreferred embodiment, it is not intended to limit the scope of theinvention to the embodiment illustrated, nor otherwise than the terms ofthe subjoined claim.

What is claimed is:

In a rotary machine,,the combination with acircular frame provided withtwo ports for a fluid to be translated, a pair of discs disposed in saidframe in parallel spaced relation with respect to each other, one ofsaid discs being stationary and the other disc being mounted forcircular movement of translation with respect to the stationary disc,the diameter of said movable disc being larger than that of saidstationary disc, two cooperating spiral bands carried each by one ofsaid discs, one engaged in the other so as to be tangent at two pointsof each convolution of each band to provide a central fluid workingchamber of variable volume and lateral working chambers which moveduring circular translation movement of said movable disc, and conduitmeans to establish a communication between said central working chamberand one of said ports, the other said port being connected to a portadjacent the periphery of said movable and stationary discs, guidingmeans for said movable disc including a plurality of circular orificesformed through said movable disc and distributed therearound between theperiphery of said movable disc and the periphery of said stationarydisc, a plurality of rotatable shafts each provided with an eccentricand supported by said frame to extend through one of said orifices, withsaid eccentric cluding a common central drive shaft drivingly connectedto each 0t said rotatable shafts.

References Cited in the file of this patent UNITED STATES PATENTS801,182 Creux Oct. 3, 1905 1,376,291 Rolkerr Apr. 26, 1921 2,324,163Montelius July 13, 1943 2,475,247 Mikulasek July 5, 1949 2,494,100Mikulasek Jan. 10, 1950 2,809,779 Girvin Get. 15, 1957 FOREIGN PATENTS30,272 France Dec. 31, 1925 101,757 Sweden June 10, 1941 813,559 FranceMar. 1, 1937 980,737 France Ian. 3, 1951

